1. Field of the Invention
The present invention relates to a ceramic electronic component including a multilayer ceramic capacitor, for example.
2. Description of the Related Art
Recently, with quick progress toward smaller sizes and higher functionality of electronic components, downsizing of multilayer ceramic capacitors mounted to the electronic components has also been demanded. In the case of the multilayer ceramic capacitor, for example, a capacitor having a high electrostatic capacity and being replaceable with an aluminum electrolytic capacitor has been commercialized with development of the film thinning technology and the multilayer technology.
As illustrated in FIG. 9, a multilayer ceramic capacitor 2 as a main body of an electronic component includes a bare ceramic body 5 in which a plurality of ceramic layers 3 and a plurality of inner electrodes 4 are alternately stacked. Adjacent ones of the plural inner electrodes 4 are alternately led out to opposing end surfaces of the bare ceramic body 5. Outer electrodes 6 electrically connected to the inner electrodes 4 are formed on the end surfaces of the bare ceramic body 5 to which the inner electrodes 4 are led out. With such a configuration, an electrostatic capacity is formed between the outer electrodes 6 disposed on the opposing end surfaces of the bare ceramic body 5. The multilayer ceramic capacitor 2 is mounted to a mounting substrate 7 by solders 6a for mounting. At that time, the outer electrodes 6 of the multilayer ceramic capacitor 2 are attached to the mounting substrate 7 by the solders 6a for mounting.
In the multilayer ceramic capacitor 2 described above, a ferroelectric material having a comparatively high dielectric constant, e.g., barium titanate, is generally used as the ceramic layers 3. However, because such a ferroelectric material exhibits the reverse piezoelectric effect, mechanical distortions occur in the ceramic layers 3 upon application of an AC voltage to the multilayer ceramic capacitor 2. When resulting vibration is transmitted to the mounting substrate 7 through the outer electrodes 6, there is a possibility that the mounting substrate 7 may become an acoustic radiation surface in its entirety and noisy vibration sounds (acoustic noises) may generate.
One example of solutions to cope with the above-described problem is, as illustrated in FIG. 10, to connect a pair of metal terminals 8 to the outer electrodes 6 of the multilayer ceramic capacitor 2 by soldering, and to solder the metal terminals 8 to the mounting substrate 7 such that a space is kept between the mounting substrate 7 and the multilayer ceramic capacitor 2. With such a configuration, the mechanical distortions occurring in the ceramic layers 3 upon application of the AC voltage can be absorbed by elastic deformations of the metal terminals 8, and the resulting vibration can be suppressed from being transmitted to the mounting substrate 7 through the outer electrodes 6. Thus, generation of noises can be reduced (see FIG. 21 in Japanese Patent No. 3847265).
However, a ceramic electronic component 9 described in Japanese Patent No. 3847265 includes a problem that, because the multilayer ceramic capacitor 2 and the pair of metal terminals 8 are fixedly connected to each other by soldering, the solders may be melted due to heating in a reflow process when the multilayer ceramic capacitor 2 is mounted to the mounting substrate 7, and the multilayer ceramic capacitor 2 may be detached from the pair of metal terminals 8.
Meanwhile, a lead-free high-temperature solder has recently been used as a bond for bonding the multilayer ceramic capacitor 2 and the pair of metal terminals 8. Such a solder is endurable against high temperatures up to a certain level. However, the general reflow temperature is about 220° C. to 260° C. Accordingly, even when the lead-free high-temperature solder is used as the bond, there is a fear that the bond may be melted depending on setting temperature, and the multilayer ceramic capacitor 2 may be detached from the pair of metal terminals 8.